Piston Ring Installation - Mercury 40 Service Manual

1.050 in. (26.7 mm)

Piston Ring Installation

IMPORTANT: Piston ring side with mark must be
facing up.
Piston rings are tapered on the top side, and flat (rect-
angular) on the bottom side (half-keystone rings).
Note that top ring is chromed and bottom ring is steel.
CAUTION
Care must be taken not to scratch the side sur-
faces of ring groove. Scratching this area will
damage the ring groove.
90-852572R1 JANUARY 1998
Piston Ring
Enlarged View of
Piston Ring Grooves
1. Install piston ring in appropriate groove on piston
using Piston Ring Expander Tool. Spread rings
just enough to slip over piston.
Top Groove – Chromed Ring
Bottom Groove – Steel Ring
2. Check piston rings to be sure they fit freely in
groove. Lubricate rings and cylinder wall with
2-cycle oil.
b
a - Piston Ring Expander (91-24697)
b - Piston Rings
3. Align piston ring end gaps with ring locating pins
as shown. Check locating pins making sure they
are tight.
a
b
a - Locating Pin
b - Piston Rings
a
PE-51081
a
b
PE-51228
a
PE-51082
POWERHEAD - 4-31